Piston ring



Dec. 24, l 92 9.

A. M. ,FARMER PISTON RING Filed July 27, 1.923

W6 M w m My 6/ a 9 Kg W w Mw. B 14 reamed an 24, 1929 ALBERT El.FAEWZER, @Ii' CHECAEG, 114 MB? @3113 I Application shied July 2'2, i923.

This invention relates to a packing ring for pistons, and moreparticularly to pistons oi internal combustion engines.

Packing rings of this type as usually con: 5 structed are splitexpansion rings mounted within grooves in the piston and in the commonform of such rings, the natural tendency of the rin itself to expand isdepended upon to keep t e ring in close contact with the cylinder walland prevent leakage past the piston. In order to insure against leakage,these rings when first inserted have a greater expansion force than isnecessary to keep them tight, and as they wear they gradually becomeloose, or the force which holds them against the cylinder wall becomesless and allows leakage. In other types of rings common upon the market,a spring is placed inside the ring within the groove to exert an outwardforce on the ring and hold it in firm contact withthe cylinder wall, butin allconstructions where expansion of the ring is caused by a forceinherent within thering itself, or by separate mechanical means employedin connection with the ring, the expansive force is too great at timesand in use soon becomes insufiicient.

The object of the present invention is to so construct the ring itself,that it will be expanded at all times firmly against the cylinder wallby the force of compression of fluid within the cylinder, and further,to so construct the ringthat it will not only be expanded outwardlagainst the cylinder wall, but will also e held in firm contact with oneside of the groove in which it is placed to prevent leakage not onlybetween the ring and the cylinder wall, but also past the ring throughthe groove. These objects are attained through the configuration of therin itself and without the employement of umIue inherent expansion inthe ring or separate means employed in connection with the ring, thenecessary force for holding the ring expanded and against a wall of itsgroove, being provided by the internal pressure within the cylindercaused by compression of fluid therein, and therefore the force withwhich the ring is held against these contact surfaces is always indirect proportion to the Semal No. 854,321.

force of compression within the cylinder and is not dependent upon theexpansive force oi the ring itself or expanding ring elements employedin connection therewith. The ring is therefore held at all times inclose contact with the cylinder wall and groove side, greatly increasingthe life of the ring and causing it to form a tight joint at the timethat such joint is most required.

It is also an object of the present invention to provide certain othernew and useful features in the construction, all as hereinafter morefully set forth.

With the above and other ends in view, the invention consists in thematters hereinafter set forth and more particularly pointed out in theappended.- claim, reference being had to the accompanying drawing, inwhich Figure 1 is a side elevation of a piston with" parts broken awayand in section, and showing a plurality of packin rings embodying theinvention, place wit in grooves in the wall of the piston;

Fig. 2 is a plan view-of one of the rings detached;

Fig. 3 is an edge elevation of the ring shown in Fig. 2, and

Fig. 4 is an enlarged sectional detail of -a portion of the piston walland adjacent cylinder wall, with a ring shown in section within a groovein the piston wall.

In order to secure a ring having the necessary inherent expansivetendency, it is the usual practice to form such rings with an inner wallwhich is eccentric to the outer wall of the ring, that is, the center ofits inner circle is oiiset relative to the center of its outer circle,but in the present invention, as the inherent expansion of the ring isnot depended upon to hold it in firm contact with the cylinder wall, thepresent ring may be formed with concentric surfaces and by splitting thering in the usual manner, forming the usual step joint, the ring is freeto expand against the cylinder wall.

' In order that the force of fluid compression within the cylinder maybe employed to expand the ring, the ring which is indicated as a wholeby the numeral 1, is formed at one-side with an outstanding annular ribor H, I i

v .flange2 the outer surface of such flange being in e plane of'theouter surface of the ring .which contacts with the wall of the cylinder.The ove Gin the wall A of the piston is forme of a size so that the ring1 will fit therein and slide freely to expand into firm contact with thewall of the cylinder. To provide a space in the iston wall adjacent thecove C for the an ar rib 2, the piston wall is cut away at one side ofthe groove to conform approximatelyto the inner side of the annular rib2, which inner side surface is preferably formed at an angleofapproximately to the outer contact surface of the ring. The ringswhich are placed in the grooves adjacent the upper end of the piston areplaced with their annular ribs 2 extending upwardly or toward the upperend of the piston, and thering or rings adjacent the lower end of thepiston are preferably placed with the annular rib or flange extendingdownwardly or'toward the lower end of the piston. Therefore upon theup-stroke of the piston and the compression of fluid within thecylinder, this compressive force passing downward. between the pistonand cylinder wall comes against the inner side of the upstandingannular. rib or flange 2, and thus exerts a force thereon to expand thering into firm contact with the wall of the cylinder. As

this inner surface of the rib is inclined inwardly and downwardly, theforce thereon of the compressed fluid will tend not only to the ring isoperated in connectionlwith the venous sizes and types of pistons. It isalso obvious that other changes in the form and construction of the ringwhich fall within the scope of the appended claim are contemplated, andI therefore do not limit myself to the construction shown.

What I claim is V Y 'A piston rin havin a rib at the inner base edgethereo said ri having a surface coplanar with the base and anothersurface sloped from the base plane upwardly and outwardly of the ring,thereby forming a knife edge adapted to engage the base of a piston ringgroove, said ring also aving another rib at the upper outer edge thereofs id latter rib havin a surface co-planar wit he outer wall of t e ringand another surface slopedfrom the last named surface downwardly andinwardly to the top of the ring, thereby forming a knife edge adapted toengage a cylinder wall;

In testimony'whereof I afiix my signature.

ALBERT M. FARMIER.

expandthe ring, butalso to force it into firm frictional contact withthe lower side of the groove in which the ring is mounted. This forcingand holding of the ring against the bottom wall of the groove preventscompression from passing by the ring. through the groove, and suchescapeof compression is further guarded against by providing a second annularflange or rib 3 at the inner side of the ring adjacent the bottom of thegroove, with the lower side surface of this rib in the plane of thelower side surface of the ring and with the upper side surface of therib or flange inclined upwardly and outwardly and meeting the lowersurface at an angle of substantially 45. 1 The force of compressed fluidpassing into the groove behind the ring therefore comes upon the upperside of this flange 3, exerting a force thereon which further assists inholding the ring firmly down upon the bottom of its groove and alsoforcing the ring outwardly orexpanding it-in its groove. If founddesirable, an annular groove 4 may be formed in the outer contactsurface of the ring, forming an oil groove to carry oil for the purposeof lubricating the surface of the cylinder.

Obviously, the configuration of the ring may be varied to suit theconditions of use, and the particular form, arrangement and number ofannular ribs or flanges may also be varied to suit the conditions underwhich

